1. Field of the Invention
The present invention relates to an image processing apparatus of image data photographed by a digital video camera or the like and, more particularly, to an image processing technique for superimposing bit map data to moving image stream data.
2. Description of the Related Art
There is a recording apparatus such as a video camera or the like for recording, together with moving image data, additional information such as date and time of a moving image photographing and photographing camera information onto a recording medium such as digital versatile disk (DVD), hard disk drive (HDD), memory card, or the like.
In such a recording apparatus, the moving image data is compression-encoded by using a method such as MPEG2, H.264, or the like and recorded.
The additional information is generated as bit map data and then is run-length encoded.
The encoded moving image data and bit map data are multiplexed into an MPEG-TS (transport stream) generateat and recorded onto the recording medium as a steam file of the TS format.
Since the additional information is overlay bit map data (caption data) which has been multiplexed into the stream of the TS format, it can be reproduced and displayed by a reproducing apparatus which conforms with a display rule of the overlay bit map data.
From such a situation, in the Official Gazette of Japanese Patent Application Laid-Open No. 2009-49726, such a technique that the additional information recorded in the stream as meta data in accordance with a unique rule is converted into overlay bit map data and recorded has been proposed. By such a technique, such additional information can be reproduced and displayed even in the reproducing apparatus which conforms with the display rule of the overlay bit map data.
However, since the bit map data is very large data, there is such a problem that unless a bit rate of the moving image data is not reduced, a bit rate of the whole moving image processing system cannot be maintained, when a large amount of additional information is multiplexed.
It is, therefore, an object of the invention to provide an image processing apparatus which can efficiently multiplex bit map data to image data in a moving image processing for multiplexing an overlay bit map to a moving image.